Planning to install a custom ROM on my Evo 3D, have some questions first

First I want to say that today's Carrier IQ story is what finally has pushed me to the edge as for as hacking my phone.

I do not know too much about the matter, but I have had a few people recommend Cyanogenmod, and I will probably go down that road unless someone has any other suggestions. The CM website does list the Evo 3D as a supported device, and it even has a wiki page explaining how to go about installing it.

My questions are the following:

It warns that installing CM voids your warranty. I had no illusions of getting support while CM was installed on the phone, but are you not able to restore it to the way you got it from your carrier and getting support then? Or is there some low level software change that takes place during the process?

Is there another custom ROM that is better suited for the Evo 3D?

What should I back up if anything? Seeing as contacts are stored in Google and I was under the impression that it also stores a list of all your apps from marketplace.

EDIT: Looks like my phone has Hboot 1.5, I believe that makes things more difficult.